my old thermstat has only two wires how can i connect it to RTH8500 honeywell thrmostat

Same issue with the RTH8500, I have a forced air gas furnace and only two wires going from the unit to the old thermostat. (don't rightly know what colors they are as the wiring from the furnace to the thermostat was a hack job splicing 3 different lengths of wire together)

my old thermstat has only two wires how can i connect it to RTH8500 honeywell thrmostat

Same issue with the RTH8500, I have a forced air gas furnace and only two wires going from the unit to the old thermostat. (don't rightly know what colors they are as the wiring from the furnace to the thermostat was a hack job splicing 3 different lengths of wire together)

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WE R GOING FROM A HONEYWELL TAYSTAT500 THERMSTAT (HEAT PUMP) TO A NEW HONEYWELL to (WHOLE NEWHEATING/AIR CONDITIONER) WITH A HONEYWELL RTH8580WF1007 THERMOSTAT? WHERE WOULD THE C WIRE BE. WE DO NOT HAVE A WIRING SCHEMATIC FOR THE OLF THERMOSTAT. IT HAS 7 WIRES. HELP?

You will need the installation book that came with the thermostat. There is a way to enter into the programming of the thermostat from the home screen. From there, you will need to find what code is the temperature settings in the manual, they are usually all 3 digit numbers. Once you find the code for the setting your looking for which is the lowest temp for the thermostat, it will have a 75 to the right of it which you can set a lower number. Sorry I do not have the manual right now to just tell you exactly how, but hope this still helps!

Is this a new hvac system? A new furnace can work differently than your old one. Does it shut off after a minute or two or continue to run? If it continues to run then call that professional back and let him fix it. If it shuts down after a minute or two then it is a feature of the new thermostat to squeeze all of the cool it can from the a/c coil and ductwork.Some of them have settings that you can adjust for blower delay on and off, read the manual that came with the t-stat and see if it does.